Method of performing balloon dissection

ABSTRACT

A retractor for use in arthroscopic surgery. The retractor has a mechanical expanding portion for expanding against sub-surface tissues when the retractor is in use. The retractor also has a fluid-operated expanding portion, which may be independently controllable, for expanding against sub-surface tissues when the retractor is in use. The retractor is inserted through a small percutaneous opening, expanded in sub-surface tissues without significantly damaging the tissue, then collapsed after use for removal. The retractor can be manipulated to allow the surgeon to push or pull or lever on tissue. The retractor can be hollow like a cannula to permit the passage of one or more surgical devices through the retractor, with a side portal into the center of the retractor.

RELATED APPLICATIONS

This application is a division of and claims the benefit of copendingapplication Ser. No. 08/029,695 filed Mar. 11, 1993. The aforementionedapplication Ser. No. 08,029,695 is itself a divisional of applicationSer. No. 07/631,749, filed Dec. 18, 1990 (now U.S. Pat. No. 5,197,971).The aforementioned application Ser. No. 07/631,740 is itself acontinuation-in-part of and claims the benefit of application Ser. No.07/609,341, filed Nov. 5, 1990 (now abandoned). The aforementionedapplication Ser. No. 07/631,740 is also a continuation-in-part of andclaims the benefit of the filing date of application Ser. No.07/487,645, filed Mar. 2, 1990. The benefit of the earlier filing dateof the aforementioned application Ser. Nos. 08/029,695; 07/631,740;07/609,341; and 07/487,645 is claimed for all subject matter common tothis application.

BACKGROUND OF THE INVENTION

The present invention relates to expandable subsurface devices for usein surgery. More particularly, the present invention relates toselectively expandable retractors for use in selectively andspecifically moving sub-surface tissue in arthroscopic surgery,endoscopic surgery and fiber optic surgery. (The term "arthroscopicsurgery" as used in this application includes endoscopic surgery, fiberoptic surgery, and any other type of surgery on sub-surface tissues.Such surgery is performed percutaneously through a small incision oropening in the skin, as opposed to open surgery in which the surgeoncuts through and opens up all superior tissue until all the operatingarea is exposed.)

Arthroscopic surgery is currently performed without suitable tools forspecifically moving tissue and creating visualization and workingspaces. Generalized expansion is obtained with CO₂, H₂ O, etc. However,this technique leaves fluid everywhere and is not useful to specificallymove tissue.

There are no devices available which allow a surgeon to selectivelyposition various tissue masses encountered during arthroscopic surgery.Delicate tissue such as nerve tissue or blood vessels is put at risk andcan be damaged during an operation. Furthermore, the limited spaceavailable for the surgeon to work in could make an operation moredifficult than it could be.

Retractors designed for use in open surgery are unusable in arthroscopicsurgery. Current bladder devices such as a Foley catheter or those usedin percutaneous transluminal coronary angioplasty are not useful toretract tissue in arthroscopic surgery, because they are made of a soft,pliable, flimsy material; they work with relatively low pressure; andthey have smooth walls and a large surface area of contact so as not todamage the delicate tissues. Such bladder devices also inflate into anonspecific shape, assuming the shape of whatever surface or object theyencounter. They do not expand or retract at or near the tip, are notrigid enough to be insertable within a joint or among muscles, tendonsand bones, and are too flexible to permit specific tissue retraction.Bladders can also be perforated during surgery.

Such bladder devices also do not provide enough force to move tissue asneeded in arthroscopic surgery, mainly because they are designed todilate an existing stretchable space within the body, such as a bloodvessel, and not to create an actual space from a potential space such asin the subacromial bursa or carpal tunnel. In contrast, a great dealmore force is needed to selectively move tissues such as muscles, bones,and tendons and expand a potential space therein. One must have astrong, sufficiently rigid instrument to do this, and exert much moreforce and yet protect delicate tissues. One also needs the ability tospecifically direct force in specific locations or directions, notmerely randomly. A bladder such as a Foley catheter would deform in anuncontrolled fashion, not pushing where it is needed most.

Accordingly, there exists a need for instruments suitable tomechanically specifically move tissue, which are small enough to fitthrough a small opening in the skin and which expand to create a workingand visualization space in sub-surface tissues. Such instruments must bestrong enough and precise enough for use in arthroacopic surgery. Myco-pending applications identified above disclose devices suitable forsuch applications. This application is based on those applications anddevices.

SUMMARY OF THE INVENTION

The present invention is a mechanically and pneumatically expandableretractor suitable for arthroscopic surgery and removable thereafterwithout significantly damaging the moved or retracted tissue. Theretractor has a distal end and a proximal end. The retractor includes amechanical expanding portion for expanding against sub-surface tissueswhen the retractor is in use, and a fluid-operated expanding portion forexpanding against sub-surface tissues when the retractor is in use. Thefluid-operated expanding portion can be axially co-extensive with themechanical expanding portion of the retractor, or it can be placedelsewhere along the length or at the tip of the retractor. Thefluid-operated expanding portion can expand either independently of orin conjunction with the mechanical expanding portion of the retractor.

The retractor preferably has a rigid shaft to allow the surgeon to applyforce to sub-surface tissues by pulling or pushing on the retractor, orby using it as a lever. Alternatively, the shaft can be flexible,allowing the retractor to be positioned around a curve or corner andallowing the surgeon to pull back on the retractor to move tissuethereby.

In an alternative embodiment, the bladder is not fluid-expanded, butrather covers the mechanical expanding portion to separate it fromtissues it contacts.

The retractor may have one or more central passages to function as acannula. Alternatively, the retractor can be solid or needle-like withor without a removable trocar.

The retractor is contracted after use and removed from the body tissueswithout having significantly damaged the tissues.

The retractor provides the surgeon with the ability to selectively moveor retract tissue and to expand a specific space, and to gain avisualization and working space, a function which is not available inpresent operating instruments.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the present invention will become apparent to thoseskilled in the art to which the present invention relates from readingthe following specification with reference to the accompanying drawings,in which:

FIG. 1 is a view of a cannula type retractor in accordance with thepresent invention, having a plurality of expanding arms, shown in anunexpanded condition;

FIG. 2 illustrates the retractor of FIG. 1 in an expanded condition;

FIG. 3 is a side elevational view of the body of the retractor of FIG.1;

FIG. 4 is a longitudinal sectional view of the nut of the retractor ofFIG. 1;

FIG. 5 is a side elevational view of the sleeve of the retractor of FIG.1;

FIGS. 6A-H, J and K are a series of views illustrating the retractor ofFIG. 1 and similar retractors in an expanded condition;

FIG. 7 is a view of a retractor having two axially spaced expandingportions, shown in an unexpanded condition;

FIG. 8 illustrates the retractor of FIG. 7 in an expanded condition;

FIG. 9 is a view of a retractor in accordance with the presentinvention, and also having an expandable bladder, shown in an unexpandedcondition;

FIG. 10 illustrates the retractor of FIG. 11 in an expanded condition;

FIG. 11 is a view showing a retractor being used in carpal tunnelsurgery, in an unexpanded condition;

FIG. 12 is a simplified transverse sectional view of the operating areaof FIG. 11;

FIG. 13 is a view similar to FIG. 11 with the retractor in an expandedcondition;

FIG. 14 is a simplified transverse sectional view of the operating areaof FIG. 13;

FIG. 15 is a view of a non-cannula type retractor in accordance with thepresent invention, shown in an unexpanded condition;

FIG. 16 illustrates the retractor of FIG. 15 in an expanded condition;

FIG. 17 is an illustration of the use of a pair of retractors inarthroscopic shoulder surgery, with the retractors shown in anunexpanded condition;

FIG. 18 is an illustration similar to FIG. 17 with the retractors shownin an expanded condition;

FIG. 19 is a view of an elliptically shaped mechanical retractor, in anunexpanded condition;

FIG. 20 shows the retractor of FIG. 19 in an expanded condition;

FIG. 21 is an end view of the retractor of FIG. 20;

FIG. 22 is a view of a mechanical retractor with an independentlyoperable pneumatic bladder retractor, both at the distal end, in anunexpanded condition;

FIG. 23 shows the retractor of FIG. 22 in an expanded condition;

FIG. 24 is an end view of the retractor of FIG. 20;

FIG. 25 illustrates a retractor having a pair of axially spacedexpanding portions each being mechanically and pneumatically expandable;

FIG. 26 is an end view of the retractor of FIG. 25;

FIG. 27 is a view of a mechanical retractor with an independentlyoperable pneumatic bladder retractor at a separate axial location, in anunexpanded condition;

FIG. 28 shows the retractor of FIG. 27 in an expanded condition;

FIG. 29 is a view of a mechanical retractor with an independentlyoperable pneumatic bladder retractor disposed therein, in an unexpandedcondition;

FIG. 30 shows the retractor of FIG. 29 in an expanded condition;

FIGS. 31A-H and J illustrate a variety of shapes for the pneumaticallyexpandable retractor portion;

FIG. 32 is a view of a mechanical retractor having a pneumatic bladderas the motive force for expansion, in an unexpanded condition;

FIG. 33 shows the retractor of FIG. 32 in an expanded condition;

FIG. 34 is a view of another mechanical retractor having a pneumaticbladder as the motive force for expansion, in an unexpanded condition;

FIG. 35 shows the retractor of FIG. 34 in an expanded condition;

FIG. 36 is a view of mechanical retractor for separating tissue having apneumatic bladder as the motive force for expansion, in an unexpandedcondition;

FIG. 37 shows the retractor of FIG. 36 in an expanded condition;

FIG. 38 is a view of a pneumatic bladder retractor with mechanical arms,in an unexpanded condition;

FIG. 39 shows the retractor of FIG. 38 in an expanded condition;

FIG. 40 illustrates a mechanical retractor with a non-pneumatic bladdersecured to a mechanical expanding portion, in an unexpanded condition;

FIG. 41 shows the retractor of FIG. 40 in an expanded condition;

FIG. 42 illustrates another mechanical retractor with a non-pneumaticbladder secured to a mechanical expanding portion, in an unexpandedcondition;

FIG. 43 shows the retractor of FIG. 42 in an expanded condition;

FIG. 44 illustrates a mechanical retractor with a mesh-typenon-pneumatic bladder secured to a mechanical expanding portion, in anunexpanded condition;

FIG. 45 shows the retractor of FIG. 44 in an expanded condition;

FIG. 46 is a top plan view of an apparatus for guiding an arthroscopeand a cutting device; and

FIG. 47 is a longitudinal sectional view of the apparatus of FIG. 46.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

By way of example, FIGS. 1-5 illustrate an arthroscopic retractor 10 inaccordance with the present invention. The retractor 10 includes aretractor body 12, a retractor sleeve 14 and a nut 16.

The hollow tubular retractor body 12 (FIG. 3) includes a central portion18, a widened distal end portion 20, and a threaded proximal end portion22. The distal end portion 20 is of a larger diameter than the remainderof the retractor body 12. A pair of diametrically opposed notches 24,only one of which is seen in FIG. 3, are formed in the distal endportion 20. A central passage 26 extends longitudinally the entirelength of the retractor body 12. The passage 26 is large enough forarthroscopic surgical instruments to pass through. The central portion18 is rigid to allow manipulation of the distal end portion by movingthe proximal end portion. Alternatively, the central portion could beflexible for easier positioning in the body. The threaded proximal endportion also includes suitable means (not shown) such as a clamp to hookup arthroscopic instruments, or to lock the retractor 10 on to such adevice.

The nut 16 (FIG. 4) includes a body portion 30 having a threaded bore 32for receiving the threaded end portion 22 of the retractor body 12. Thenut 14 is enlarged to form a pair of handles 34 which extend from thebody portion 30 of the nut 16. The handles 34 can be grasped by asurgeon to rotate the nut 16, and to manipulate the retractor 10 as awhole. An annular slot 36 is formed in the distal end portion of the nut16.

The hollow tubular retractor sleeve 14 (FIG. 5) includes a centralportion 40, a proximal end portion 42, and a distal end portion 44. Theproximal end portion 42 has an oblong widened portion 46 which isreceived in the slot 36 in the nut 16. The distal end portion 44 has apair of diametrically opposed projections 48, only one of which is shownin FIG. 5. The projections 48 are received in the notches 24 in thedistal end portion 20 of the retractor body 12. A central passage 50extends longitudinally through the entire length of the retractor sleeve14. The passage 50 is sized to receive the central portion 18 and theproximal end portion 22 of the retractor body 12. The central portion 40is rigid to allow manipulation of the distal end portion by moving theproximal end portion. Alternatively, the central portion could beflexible for easier positioning in the body.

The retractor sleeve 14 also includes an expanding portion 60. Theexpanding portion 60 includes a plurality of circumferentially spacedexpanding arms 62. Adjacent arms 62 define between them a series ofslots 64. The expanding portion 60 illustrated in the embodiment ofFIGS. 1-5 has eight equally spaced arms 62 over a 360° range. It shouldbe understood that the present invention contemplates that any differentnumber of arms can be used, and they can be spread equally or unequallyover a different circumferential extent, in order to provide varying oreccentric expansion.

Each expanding arm 62 extends between a groove 66 adjacent the distalend portion 44 of the sleeve 14, and a groove 68 adjacent the centralportion 40 of the sleeve 14. The grooves 66 and 68 are formed on theexterior of the material of the sleeve. An intermediate groove 70 isformed on the interior of each arm 62 and divides each arm 62 into adistal expanding portion 72 and a proximal expanding portion 74. Thegrooves 66, 68, and 70 weaken the material of the sleeve 14. When forceis directed axially on the distal end portion 44 of the sleeve 14 in adirection toward the proximal end portion, the material of the sleeve 14buckles at the weakened areas of the grooves 66, 68, and 70, causing thearms 62 to expand radially outwardly.

To assemble the retractor 10, the hollow sleeve 14 is slid axially overthe proximal end portion 22 of the body 12. The distal end portion 44 ofthe sleeve 14 engages the widened distal end portion 20 on the body 12.The projections 48 on the sleeve 14 engage the notches 24 on the body12, blocking rotation of the sleeve 14 relative to the body 12. (Otherstructures can be used to obtain this blocking function. For example, ifthe retractor parts are injection molded, a key and keyway structure maybe used for ease of manufacture.) At least a portion of the threadedproximal end portion 22 of the body 12 is exposed. The nut 16 isthreaded onto the exposed proximal end portion 22 of the body 12. Thewidened portion 46 of the sleeve 14 is received in the slot 36 in thenut 16.

To operate the retractor 10, the nut 16 is rotated on the threadedproximal end portion 22 of the body 12, decreasing the distance betweenthe nut 16 and the distal end portion 20 of the body 12. The sleeve 14is compressed axially. The sleeve 14 buckles at the grooves 66, 68, and70. The arms 62 on the sleeve 14 move radially outwardly from anunexpanded condition as shown in FIG. 1 to an expanded condition asshown in FIG. 2. (Any system for shortening the sleeve other than athreaded system can be used also.)

The radially outermost surface 78 of each expanded arm 62, which is theradially outermost point of the retractor 10, is located axially at thedistal end of the retractor 10. Because the retractor 10 expands at itsdistal end, not at a mid-portion, stability is increased, since thesurgeon is holding the retractor 10 at its proximal end and theretractor 10 is firmly positioned at its distal end. Also, the expandedretractor 10 thus creates a working space where the surgeon needs it,without having to go further down with the instrument as would benecessary if the expanding portion were axially centrally located. Theretractor 10 is rigid in a transverse direction, and therefore thesurgeon can pull push or lever it to manipulate subcutaneous tissue.

There are a variety of ways in which the expanding portion of aretractor in accordance with the present invention can be configured forparticular surgical applications. In the retractors shown in FIG. 6, theexpanding arms 62 are disposed irregularly circumferentially around theretractor to provide an increased working space or operating areabetween particular pairs of expanding arms 62. The external shape of theretractor when expanded, and the amount of expansion, are designed forthe specific application on which that retractor is to be used. Forexample, if the surgeon is working against bone, he can select aretractor which is configured so that it stays flat against the bone,and expands away in the opposite direction, to push tissue away from thebone and create a working and visualization space next to the surface ofthe bone.

The retractor of the present invention, therefore, is not merely a roundstructure which expands. It allows mechanical manipulation of tissue, afunction which is not available now in arthroscopic surgery. It can bein the shape of an umbrella; oval; wedge; cone; triangular; I-beam; ahalf-moon shape to protect a nerve; a V-shape to push a nerve in adifferent direction; a V-shape which expands at the tip; T-shaped orL-shaped; or other shapes as desired.

As an example, the retractor 10a (FIG. 6) includes a sleeve 14a similarto the sleeve 14 of the retractor 10, but with one less expanding arm.An enlarged working space 81 is formed between the arm 82 and the arm 84of the sleeve 14a. A greater portion of the retractor body centralportion 18 is thus exposed.

Similarly, the retractor 10b includes a sleeve 14b having six expandingarms. A larger working space 85 is created between the arms 86 and 88,exposing a larger portion of the body central portion 18. In theretractor 10c, the sleeve 14c has only five radially expanding arms,creating a 180° working space 89 between the arms 90 and 92.

In the retractor 10d, six expanding arms are spaced circumferentiallyaround the sleeve 14d to expose the retractor body central portion 18 onopposite sides. A working space 93 is created between the arms 94 and 96on one side, and a working space 97 is created between the arms 98 and100 on the opposite side. In the retractor 10e, only four expanding armsare present, and even larger working spaces are created on oppositesides, that is, a space 101 between the arms 102 and 104 on one side,and a space 105 between the arms 106 and 108 on the opposite side.

It can thus be seen that the retractor 10 can be configured to meetalmost any application, by appropriately locating and sizing andconfiguring the expanding portion of the sleeve 14 of the retractor. Forexample, there may be provided longer expanding arms to provide for agreater amount of expansion. The arms may in such a case may be madethicker for greater strength. All such configurations are includedwithin the scope of the present invention.

Also included are structures functionally equivalent to the expandingarm construct. For example, the expanding portion of a retractor inaccordance with the present invention may be as simple as an expansiondevice like a screw jack or an inflatable bladder disposed between twoopposed plates which spread apart upon actuation of the expansiondevice. A cable can be used to pull on a part to cause expansion. Or, acam-operated mechanism can be used with a sliding or rotating part tocause expansion.

The central passage 26 through the body portion of the retractor 10effectively allows the retractor 10 to serve as a cannula through whichsurgical instruments can be passed even when the retractor is in use. Ifa side portal is provided in the retractor as described below, surgicalinstruments, tools, fluid lines, etc. can be passed into or out of theretractor through the side portal.

Another important feature of the retractors of the present invention isthat they can be contracted after use of the retractor to allow theretractor to be removed from the operating area. The structure of theretractor allows for safe decompression (contraction) and removal of thedevice after use. For example, in the retractor illustrated in FIGS.1-5, the widened portion 46 of the retractor sleeve 14 is received inthe slot 36 in the nut 14. After expansion of the sleeve as describedabove, when the nut 14 is rotated back so as to move away from thedistal end portion 20 of the retractor body 12, the nut 14 pulls thewidened portion 46 of the sleeve 14, lengthening the sleeve and causingthe arms 62 to contract to their starting (unexpanded) position. Theretractor 10 can then be removed easily from the operating site, withouthaving significantly damaged any tissue. This feature is not availablewith any previous mechanical expanding devices such as expanding bonescrews.

FIGS. 7 and 8 illustrate another embodiment of the invention in which aretractor 110 includes two separate axially spaced expanding portionsand also has a side portal through which an arthroscope and/or otherarthroscopic surgical instruments may be passed.

The retractor 110 includes a hollow retractor body 112 having a distalend portion 114 with a tool hole 116 and a scope hole 118. An edge 120defines an opening or side portal 122 in the retractor body 112. Theopening 122 communicates with a central passage extending axiallythrough the body 112.

The hollow tubular retractor sleeve 124 includes an intermediate portion126, a pair of expanding portions 128 on either side of the intermediateportion 126, and a proximal sleeve portion 130. Each expanding portion128 of the sleeve 124 includes a plurality of arms 62 similar to theexpanding arms 62 in the embodiment illustrated in FIGS. 1-5. Eachcircumferentially aligned pair of arms 62 is connected by anintermediate sleeve segment such as the segments 125 and 127. In theretractor 110, the expanding arms 62 are spaced circumferentially aboutthe sleeve 14 so that the space between the intermediate segments 125and 127, as well as the space between adjacent arms 62, is aligned withthe opening 122 in the retractor body 112.

Accordingly, when the retractor 110 is expanded as illustrated in FIG.8, there is access from the central passage of the retractor body 112,through the opening 122, and between adjacent intermediate segments andadjacent expanding arms, for the passage of surgical instruments.Furthermore, the pair of expanding portions 128 move tissue out of theway at axially spaced locations along the retractor 110, to provide alarge working area extending longitudinally between the two expandingportions 128 of the retractor. In similar fashion, expanding portionslike or similar to the expanding portions 128 can be placed at selectedlocations along a retractor in accordance with the present invention, inorder to selectively retract tissue for a particular application. Two ormore separate retractors can also be used for this function.

In another embodiment of the invention, an inflatable bladder isincluded on the mechanically expandable retractor. The bladder can beco-extensive with the expanding portion of the retractor, or it can bespaced apart from the expanding portion of the retractor. The bladdercan be used independently or in conjunction with the mechanicalretractor.

FIGS. 9 and 10 illustrate an embodiment of the invention which includesan inflatable bladder circumscribing the expanding portion of theretractor. A retractor 140 includes a sleeve 14 with an expandingportion 60 including a plurality of expanding arms 62. The body portionof the retractor 140 has a pointed distal end 142 for easier passagethrough tissues. Proximal to the threaded portion 22 of the retractorbody, a portion 144 of the retractor includes a fluid supply port 146.An inflatable bladder 150 is bonded to the retractor sleeve 14 at twocircumferential, axially spaced locations 152 and 154. Appropriate fluidpassages are provided in the retractor body and the retractor sleeve toprovide fluid communication between the fluid supply port 146 and thebladder 150. The bladder can be deflated with suction.

The bladder 150 inflates and expands radially upon the introduction offluid under pressure into the fluid supply port 146. The bladder 150 canbe inflated independently of expansion of the expanding portion 60 ofthe retractor 140. Alternatively, the bladder 150 can be expanded inconjunction with expansion of the expanding portion 60 of the retractor140, in which case it may be preferable to have the bladder in the shapeof the mechanical retractor.

The bladder 150 prevents tissue from being caught in between theexpanding arms 62 to minimize tissue damage when the retractor is in useand to allow for easy contraction and removal of the retractor afteruse. The bladder 150 insures proper operation of the expanding portion60 by keeping tissues out of its way to provide more uniform retraction.The bladder 150 has a tamponade effect, lessening bleeding in thesurrounding tissues. The bladder 150 also spreads the retractive force,lessening the risk to delicate tissues such as nerve tissue.

An expandable bladder such as the bladder 150 can be provided at otherlocations along a retractor 140. For example, a bladder can be providedat a location spaced apart from any expanding portion of the retractor.Also, a bladder can be provided which spans longitudinally the distancebetween two expanding portions on a retractor. The bladder can be formedof a fluid tight material in order to maintain fluid pressure and exertgreater force against the tissues of the body. The bladder canalternatively be made of a perforate material which allows fluid flowtherethrough but which also serves to apply force against the tissue itencounters. The bladder may be reinforced, ribbed, or have a specificmolded shape. The bladder may be constructed in accordance with myco-pending application Ser. No. 487,645, filed on Mar. 2, 1990, thedisclosure of which is incorporated by reference. For example, thebladder is typically formed on a mandrel which is of a particular shapeand which is sized about half way between the unexpanded and theexpanded size of the bladder. The bladder may be thicker in some areasto expand less, and thinner in other areas to expand more. The bladdermay have ridges or areas of differing degrees of resistance tostretching or flexing. The bladder can be pre-shaped to assume a certainform when expanded. The bladder can have a dual durometer layeredconstruction, with a thin layer for fluid retention overlying a thickerlayer for shaping. The bladder can have a bellows-type construction.

One basic purpose of the bladder on a retractor of the present inventionis to maintain a separation between the expanding arms and the tissuesthey expand against. Therefore, the bladder need not be made of afluid-tight material if the bladder per se is not to be expandable. Ifdesired, the bladder can merely be a fabric, mesh, film, polymer, orother material extending over the expanding arms and moving radiallyoutwardly with them. Whether the bladder is fluid-tight or not, thematerial of the bladder can be bonded directly to the arms. The materialcan be stretchable to expand when the expanding arms move radiallyoutwardly then contract when the arms move back inwardly.

Use of only a bladder (without a mechanical retraction device) has thedisadvantage that a bladder can be punctured with a surgical knife orcutter and will collapse, losing all the retraction gained uponinflation and possibly compromising the surgery. Because the retractorsof the present invention are also mechanical in nature, this possibilityis avoided, and secure retraction is provided.

FIGS. 11 through 14 illustrate the use of a retractor 160 in accordancewith the present invention in carpal tunnel surgery. The retractor 160is illustrated in FIGS. 11 and 12 in an unexpanded condition, and inFIGS. 13 and 14 in an expanded condition. The retractor 160 is insertedthrough an incision 190 in the wrist, and underneath the transversecarpal ligament 192, adjacent the median nerve 194 of a hand 196.

The retractor 160 includes an expanding portion 161 with a plurality ofexpanding arms 62, two of which are spaced about an opening or sideportal 162 for instrument passage therethrough. An expanding bladder 164is bonded to the sleeve 166 of the retractor 160. The retractor 160 issecured in a holder 170 having a pair of grips 172 and 174. The grip 172is fixedly attached to a sleeve clamp 176 which securely clamps thesleeve 166 of the retractor 160. The grip 174 is fixedly attached to aportion 178 for engaging a widened portion 180 on the body portion 182of the retractor 160. The body portion 182 has a scope hole 184 and atool hole 186 extending therethrough. Suitable locking means can also beprovided to lock the retractor in a particular expanded condition.

FIGS. 13 and 14 illustrate the retractor 160 in an expanded condition.Relative movement of the grip 172 toward the grip 174 draws the bodyportion 182 proximally relative to the clamped sleeve portion 166,expanding the expanding portion 161. The expanding arms 62 move radiallyoutwardly to create a working or operating area 198 adjacent theligament 192. The bladder 164 is also expanded about the expandingportion 60 of the retractor 160. Tissue is not significantly damaged bythe retractor 160. After the operation is completed, the retractor 160is simply contracted or collapsed and removed from the operating site.

Because of the controlled expansion of the retractor 160, the mediannerve 194 is shielded from the operating area. Tools and an arthroscopemay be passed through the opening 162 into the operating area 198, whilethe median nerve 194 and other tissues such as tendons 200 are safelyshielded from the operating area 198. Accordingly, by use of theretractor 160, the surgeon is provided with an enlarged open area inwhich he can work on the ligament 192, and at the same time he hasprotected the median nerve 194 from the operating area. The surgeon hasfull visualization and working of the entire space, not a limited visionarea as with other systems. This type of operation can, of course, beperformed also with a mechanically expandable retractor not having abladder thereon.

Indicated schematically at 193 in FIG. 11 is means for measuring theretractive force applied by the expanding portion of the retractor 160.This can be any suitable apparatus for measuring the force needed tobring together the grips 172 and 174, for example. With the retractor ofFIGS. 1-5, a torque wrench or other instrument can be used to measurethe force needed to turn the nut 16. Similarly, any known apparatus canbe used to monitor the fluid pressure inside an expandable bladder on aretractor of the present invention. Thus, with any of the presentretractors, the expansion force can be monitored and controlled.

FIGS. 15 and 16 illustrate another embodiment of the mechanicallyexpandable retractors in accordance with the present invention. Theretractor 210 illustrated in FIGS. 15 and 16 is a non-cannula typeretractor. It does not have a central passage extending longitudinallythrough the retractor, but rather is solid or needle-like. Accordingly,the retractor 210 may be made slimmer if desired. It may be desirable touse such a non-canula type retractor in a situation where the surgeon isalready employing a cannula through which instruments and/or a scope maybe passed. The retractor may have a removable trocar also.

The retractor 210 may have a pointed distal end portion 212 for easierinsertion through tissues. (Alternatively, the retractor may be utilizedin conjunction with a removable trocar. The pointed distal end portionwould be the distal tip of a removable trocar which would be removedafter placement of the expanding portion of the retractor in the desiredlocation.) The retractor 210 has an expanding portion 60 with aplurality of expanding arms 62. Grooves 66, 68, and 70 in the sleeve 14define the arms 62 and provide weakened portions to allow for radialexpansion of the arms 62. Rotation of the nut 16 relative to thethreaded proximal end portion 22 of the retractor body 214, shortens thedistance between the nut 16 and the distal end 212 of the retractorbody. The sleeve 14 is compressed axially, and the arms 62 expandradially outwardly.

The expanding portion of the retractor 210 illustrated in FIGS. 15 and16 is oriented in the opposite direction longitudinally from theexpanding portion of the retractor shown in FIGS. 1-5. Thus, the maximumpoint of expansion is spaced from the distal end of the retractor 210.However, this configuration provides an annular end face 216 at theproximal end of the expanding portion 60. Thus, the retractor 210 isusable to pull back on tissue, or to hook tissue to move it proximally.The retractor shown in FIGS. 1-5 would in such use slide out because itsexpanding portion has a conical shape with an apex at its proximal end.This "reversed" design can be revised in practice to place the maximumpoint of expansion closer to or at the distal end of the retractor.

FIGS. 17 and 18 illustrate the use of a pair of retractors in accordancewith the present invention to perform arthroscopic surgery on theacromion 220 in the shoulder. The humeral head 222 is spaced from theacromion 220, with the rotator cuff 224 and the bursa 226 therebetween.The bursa 226 normally fits tight up against the surface 228 of theacromion 220, but is shown spaced therefrom for clarity. Because thebursa 226 is normally tight up against the surface 228 of the acromion220, it is difficult to operate on the surface 228 of the acromion 220.

To gain access to the surface 228, a pair of retractors 230 and 232 areused. The retractor 230 is inserted through an incision 234 in the back236 of the shoulder. The retractor 230 has an expanding portion 238located below the surface of the skin. The retractor 230 has aprojecting portion 240 located above the surface of the skin. Theretractor 230 has a passage 242 to allow the passage of surgicalinstruments therethrough.

The retractor 232 is inserted through an incision 242 in the side of theshoulder. An expanding portion 244 of the retractor 232 is located belowthe surface of the skin. A projecting portion 246 of the retractor 232is located above or outside of the skin. The retractor 232 has a centralpassage 248 to allow the passage of an arthroscope therethrough.

The retractor 230 is inserted through the incision 234 until itsexpanding portion 238 engages the surface 228 of the acromion 220. Theexpanding portion 238 is irregularly configured so as to stay relativelyflat against the acromion 220 and expand 180° away to push the bursa 226away from the surface 228. The expanding portion 238 is then expanded.The bursa 226 and rotator cuff 224 are forced away from the surface 228,creating a working and visualization space 250 against the surface 228.Similarly, the retractor 232 is inserted through the incision 242 untilits expanding portion 244 engages the surface 228. The expanding portion244 is then expanded. The bursa 226 and the rotator cuff 224 are forcedaway from the surface 228, enlarging the working and visualization space250.

An arthroscope is then inserted through the passage 248 in the retractor232 until its distal end is located in the space 250. A shaver is theninserted through the passage 242 in the retractor 230, until its distalend is also in the working space 250. The surgeon thus has both thearthroscope tip and the shaver in a clear volume adjacent the surface tobe worked upon. The surgeon can then remove an area of bone 252 from theacromion 220, without interference from the bursa 226 and the rotatorcuff 224 which are normally tight up against the surface 228.

The surgeon can manipulate the projecting portion 240 of the retractor230, and the projecting portion 246 of the retractor 232, to furthermove the tissues as desired. For example, the surgeon can pullproximally on the projecting portion 246 of the retractor 232 to pullthe bursa 226 and rotator cuff 224 away from the surface 228. Thesurgeon can use the retractor 230 as a lever, moving the projectingportion 240 thereof upwardly as viewed in FIG. 18 to move the expandingportion 238 relatively downwardly to move the bursa 226 and the rotatorcuff 224 away from the surface 228. Tissue is not significantly damagedby the retractor 230.

Upon completion of the operation, the expanding portion 238 of theretractor 230 is contracted or collapsed, and the retractor 230 isremoved from the operating site. The expanding portion 244 of theretractor 232 is contracted or collapsed, and the retractor 232 isremoved from the operating site. The bursa 226 and the rotator cuff 224regain their original position against the acromion 220.

In accordance with a feature of the present invention, a retractor inaccordance with the present invention need not have a round shape asshown in the drawings. Because there is no relative rotation between theretractor body and the retractor sleeve, neither must be round, and thebody and sleeve need not have the same cross-sectional configuration.For example, the retractor may have an elliptical or oblong shape if twocannulas or passages are formed therein. The shape may be flattened if aslimmer profile is needed to pass between certain tissue layers. Asquare cross-section may be provided if desired. This ability to use anyshape provides more leeway in configuring the expanding portion of theretractor, because the expanding portion does not have to have a roundcross-sectional configuration.

In accordance with another feature of the present invention, a retractorcan also function as two or more cannulas side-by-side. In those Figureswhich illustrate a cannula-type retractor having both a tool hole and ascope hole at the distal end, the tool hole and the scope hole are theends of longitudinally co-extensive passages extending through theretractor body. These passages or lumens serve as two cannulas.

As an example of these two features, FIGS. 19-21 illustrate a mechanicalretractor 260 with an elliptical cross-section and a dual-cannulaconfiguration. The retractor 260 has a pair of passages 262 and 264extending longitudinally through the retractor. The retractor 260 has anexpanding portion 266 with a plurality of expanding arms 268. Grooves270, 272, and 274 in the retractor sleeve 276 define the arms 268 andprovide weakened portions to allow for radial expansion of the arms 268.When the sleeve 276 is compressed axially the arms 268 expand radiallyoutwardly from the unexpanded condition shown in FIG. 19 to the expandedcondition shown in FIG. 20.

FIGS. 22-24 illustrate an embodiment of the invention in which aplurality of inflatable bladders are located at the distal end portionof a retractor having a mechanical expanding portion. The retractor 280has a sleeve portion 282, a body portion 284, and a nut 286 with handles288 thereon. The retractor sleeve 282 includes a pair of expanding arms290 on one circumferential side of the sleeve 282, and a pair ofexpanding arms 292 on the opposite side. Located circumferentiallybetween the arms 290 and the arms 292 are a pair of expanding bladders294 and 296. The bladders 294 and 296 are supplied with fluid underpressure through a fluid supply line 298. A central passage 300 extendsthrough the retractor 280.

The bladders 294 and 296 may work independently of the mechanicalexpansion of the retractor 280. The arms 290 and 292 are expanded byrotation of the nut 286 relative to the body portion 284, in a manner asdescribed above. The bladders 294 and 296 are inflated upon theintroduction of fluid under pressure through the fluid supply line 298.Such expansion is controllable independently of the expansion of thearms 290 and 292. Accordingly, the retractor 280 includes bothmechanical and pneumatic expansion means, which are independentlycontrollable, located at the same axial location along the retractor280. The relative configurations of the bladders and of the mechanicalexpanding arms can be varied to suit the particular application forwhich any given retractor is used.

FIGS. 25 and 26 illustrate a retractor 302 having two expanding portions304 and 306 spaced axially apart from each other. Each expanding portion304 and 306 includes a plurality of mechanically expanding arms 308 ofthe type described above. A plurality of inflatable bladder segments 310are interleaved between the arms 308. A scope hole 312 and a tool hole314 extend through the body 316 of the retractor 302 and are accessiblethrough a side portal 318. The side portal 318 is accessible through anopening 320 between adjacent intermediate sleeve sections 322 and 324 ofthe retractor sleeve 326. There is no bladder between the mechanicalexpanding arms 308 attached to the intermediate sleeve sections 322 and324. Thus, a working area 328 (FIG. 26) is created which is accessibleto the interior of the retractor 302 and from which tissue which hasbeen pushed aside upon expansion of the retractor 302.

FIGS. 27 and 28 illustrate a retractor 332 having an inflatable bladderportion spaced axially from a mechanically expandable portion. Theretractor 332 includes a sleeve 334 and a body 336. The sleeve 334 hasan expanding portion 338 and an intermediate portion 340. Acircumferentially extending bladder 342 is disposed at the distal end ofthe body 336. The bladder 342 extends most of the way about thecircumferential extent of the sleeve 334, but does not cover a portionon which is formed a side portal 344 in the sleeve 334. The bladder 342is inflatable or expandable independently of the mechanical expandingportion 338. Simultaneous expansion of both the bladder 342 and theexpanding portion 338 creates a longitudinally extending working spacebetween them, generally coextensive with the intermediate portion 340 ofthe sleeve 334. This working portion can be accessed through the sideportal 344. It should be noted that, in another configuration, theposition of the mechanical expanding portion 338 and the pneumaticexpanding portion 342 can be reversed. It should also be noted that morethan two expanding portions can be provided on one retractor. Thenumber, configuration, and placement of the expanding portions can bevaried in accordance with the particular application for that retractor.

FIGS. 29 and 30 illustrate a retractor 350 which includes a separatebladder that slides through the mechanical canula type retractor and isinflatable where needed at a location spaced apart from an expandingportion on the mechanical retractor. The retractor 350 includes a sleeve352, a body 354, and a nut 356. An expanding portion 358 is located atthe distal end of the sleeve 352, and a central passage 360 extendsthrough the canula type retractor 350. A separate inflatable bladder 362is disposed within the retractor 350, and can exit the distal end of theretractor 350 through an opening 364. The bladder 362 includes a fluidsupply line 366 extending through the retractor 350. When expanded, thebladder 362 includes a widened portion 368 at its distal end 370, and anarrower conical portion 372 located proximal to the fluid supply line366. The bladder 362 can be expanded simultaneously with the expandingportion 358, or can be expanded separately and independently as needed.

There are a variety of ways in which the pneumatic expanding portion(bladder) of a retractor in accordance with the present invention can beconfigured for particular surgical applications. The external shape ofthe bladder when expanded, and the amount of expansion, are designed forthe specific application on which that retractor is to be used. Forexample, the bladder can extend only around a circumferential sector ofthe retractor, such as 90°, to provide an increased working space oroperating area. Thus, if the surgeon is working against bone, he canselect a bladder which is configured so that it stays flat against thebone, and expands away in the opposite direction, to push tissue awayfrom the bone and create a working and visualization space next to thesurface of the bone.

The bladder is therefore not merely a round structure which expands. Itis configured to provide for selective mechanical manipulation oftissue, a function which is not available now in arthroscopic surgery.It can be in the shape of an umbrella; oval; wedge; cone; triangular;I-beam; a half-moon shape to protect a nerve; a V-shape to push a nervein a different direction; a V-shape which expands at the tip; T-shapedor L-shaped; or other shapes as desired.

As an example, a retractor 374 (FIG. 31) includes a bladder 376extending part way around the circumference of the retractor body 378. Acentral passage 380 extends through the retractor body 378 so that theretractor 374 can function as a cannula. Opposed axially extendingsurfaces 382 and 384 define a working space 386 between them.

Similarly, the retractor 388 includes a bladder 390 having opposedaxially extending surfaces 392 and 394. A larger working space 396 iscreated between the surfaces 392 and 394, exposing a larger portion ofthe body portion 398. In the retractor 400, the bladder 402 has axiallyextending surfaces 404 and 406 which create a 180° working space 408between the surfaces 404 and 406.

In the retractor 410, two expanding portions 412 and 414 are spacedcircumferentially to expose the retractor body 416 on opposite sides. Aworking space 418 is created between the arms bladder surfaces 420 and422 on one side, and a working space 424 is created between the bladdersurfaces 426 and 428 on the opposite side. In the retractor 430, theaxial orientation of the bladder 432 is reversed, so that it expands atits proximal end 434 rather than at its distal end 436. It can thus beseen that the bladder portion of a retractor of the present inventioncan be configured to meet almost any application.

In the retractors illustrated in FIGS. 32 through 37, an expandablebladder provides the motive force to separate two or more relativelyrigid mechanical pieces. The mechanical pieces perform the actual tissueretraction.

The retractor 440 (FIGS. 32 and 33) includes a pair of jaws 442 and 444pivotally mounted to a body portion 446. An expandable bladder 448 isdisposed within the retractor 440 between the jaws 442 and 444. Uponexpansion of the bladder 448, the Jaws 442 and 444 pivot radiallyoutwardly from the position shown in FIG. 32 to the position shown inFIG. 33. This retractor configuration has several advantages. First, thejaws 442 and 444 expand most at their distal ends, as opposed to themore proximal expansion of the retractor of FIGS. 1-5, for example.Second, it can in some instances be easier to shape rigid mechanicalpieces such as the jaws 442 and 444 to fit a particular application,than to shape an inflatable bladder.

The retractor 450 (FIGS. 34 and 35) includes a pair of jaws 452 and 454.The jaw 452 is fixed to the retractor body portion 456, and the jaw 454is pivotally mounted to the body portion 456. An expandable bladder 458is disposed within the retractor 450 between the jaws 452 and 454. Uponexpansion of the bladder 458, the jaw 454 pivots radially outwardly fromthe position shown in FIG. 34 to the position shown in FIG. 35. Thisretractor configuration can be advantageous when it is desired to haveexpansion occur primarily on only one side of the retractor.

The retractor 460 (FIGS. 36 and 37) includes a pair of jaws 462 and 464.The jaw 462 is fixed to or integral with the retractor body portion 466.The jaw 464 is pivotally mounted to the pointed distal end 468 of theretractor 460. An expandable bladder 470 is disposed within theretractor 460 between the Jaws 462 and 464. The bladder 470 is securedto the inside of the jaws 462 and 464. The retractor 460 also includesmeans (not shown) for providing suction as well as inflation to thebladder 470. Upon expansion of the bladder 470, the proximal end of thejaw 464 pivots radially outwardly from the position shown in FIG. 36 tothe position shown in FIG. 37. Upon the application of suction to thebladder 470, the jaw 464 pivots radially inwardly back to the closedposition shown in FIG. 36.

The retractor 460 can be used as a wedge to separate tissue layers. Thebladder 470 is first expanded to force tissue out of the way. The tissuestays apart for a period of time after being forced open. The bladder isthen contracted with suction to bring the retractor to its closedcondition. The pointed distal end 468 of the retractor 460 is then slidin further, and expanded again. The procedure is repeated as needed.Thus, the bladder is expanded and contracted to move tissue out of theway, and the retractor is gradually worked into the tissue to a depththat is required for the specific application.

In the retractor 472 (FIGS. 38 and 39), an inflatable bladder 474 isattached to an inner body portion 476 of the retractor 472. The bladder474 is also attached to the insides of a plurality of expanding fingers478. Upon inflation of the bladder 474, the fingers 478 move radiallyoutwardly to move tissue as desired. The shape and amount of theexpansion are controllable by not only the inflation of the bladder 474but also the shape and size of the fingers 478. The greatest amount ofexpansion occurs at the distal end of the retractor.

On a retractor such as those shown in FIGS. 25 and 26, the bladderfunctions to separate the mechanical expanding arms and the tissues theyexpand against. Therefore, the bladder need not be made of a fluid-tightmaterial if the expansion force is to be obtained solely mechanically.The bladder can merely be a fabric, mesh, film, polymer, or othermaterial extending over the expanding arms and moving radially outwardlywith them. The material of the bladder can be bonded to the body of theretractor or directly to the arms. The material can be stretchable toexpand when the expanding arms move radially outwardly then contractwhen the arms move back inwardly.

These features are illustrated in the retractors shown in FIGS. 40-45.The retractor 480 (FIGS. 40-41) is configured mechanically like theretractor 10 shown in FIGS. 1-5. The retractor 480 includes a bodyportion 482, a sleeve portion 484, and a nut 486. The sleeve 484 has aplurality of expanding arms 488. A central passage 490 extends throughthe retractor 480 so that the retractor 480 functions as a cannula. Abladder 492 is bonded at 494 and 496 to the body 482 and the sleeve 484.The retractor 498 (FIGS. 42 and 43) is similar except that the bladder500 thereon is bonded only to the expanding arms 502. In the retractor510 (FIGS. 44 and 45), the bladder 512 thereon is formed of afluid-permeable material such as an open-weave mesh-type fabric or othersimilar material which is biocompatible.

FIGS. 46 and 47 illustrate a retractor body portion 520 which includestwo parallel passages 522 and 524. The larger passage 522 is designedfor the passage therethrough of an arthroscope. The smaller passage 524is designed for the passage therethrough of a fiber optic laser cutteror electric cautery device. The passage 522 has a relatively long portalor opening 526, suitable for an arthroscope with a viewing angle of 10°or more. The end portion 528 of the smaller passage 524 extends at anangle to the main portion 530, and terminates in a relatively smallportal or opening 532. Thus, a device inserted through the smallerpassage 524 will exit the body portion 520 at an angle to itslongitudinal extent.

This configuration is ideal for the above-described use of a fiber opticlaser cutter or electric cautery device in conjunction with anarthroscope. The fiber optic laser cutter will cut at a locationdirectly in front of and in the field of view of the arthroscope. Fiberoptic laser cutters are available in sizes as small as 0.6 mm indiameter. The device 520 can be correspondingly small in overall size.If made of a plastic material, the device 520 electrically insulates thecutting device from the body tissues. Accordingly, the present inventionprovides structure ideally suited for enhanced arthroscopic cutting.Because the cutting device and the arthroscope are fixed in positionrelative to each other, the apparatus 520 allows direct control of boththe arthroscope and the cutting device while controlling the location ofthe retractor.

It should be noted that the apparatus 520 illustrated in FIGS. 46 and 47is suitable for use alone, that is, without the sleeve portion of theretractor. In this manner, the apparatus serves as an inserter or guidefor the arthroscope and the cutting or cautery device. The apparatus canbe fixed to the arthroscope to enhance stability. The tissue to beoperated upon can be retracted with a separate arthroscopic retractor atthe work area.

In each of these retractors, the bladder prevents tissue from beingcaught in between the mechanical expanding arms. This minimizes tissuedamage when the retractor is in use, and allows for easy contraction andremoval of the retractor after use. The bladder insures proper operationof the mechanical expanding portion by keeping tissues out of its way toprovide more uniform retraction. The bladder also has a tamponadeeffect, lessening bleeding in the surrounding tissues. The bladder alsospreads the retractive force, lessening the risk to delicate tissuessuch as nerve tissue.

In accordance with another feature of the present invention, theretractors incorporate a projecting portion at their proximal ends formanipulating the retractor. The projecting portion projects from thesurface of the body tissues when the retractor is in use. In FIGS. 1-5,for example, the proximal end portion 22 of the retractor body 12 andthe proximal end portion 42 of the sleeve 14, along with the nut 16,project from the surface of the body tissues when the retractor is inuse. The retractor 10, when expanded, can thus be used to pull or pushon tissue to move the tissue subcutaneously. Similarly, the retractor160 illustrated in FIGS. 11 through 14 has parts projecting outwardly ofthe incision 190 to allow external manipulation of the sub-surfaceportion of the retractor.

This external projecting portion (or handle) is useful in many ways. Itallows the surgeon to move tissues at will by pulling or pushing on theretractor or using it as a lever to move tissue subcutaneously. Thesurgeon can control the working point deep within the tissues because hecan control the exposed portion of the retractor. Also, it allows thesurgeon to block fluid flow, as an expanded retractor can be pulled backto seal flow and give more room to see and work. The retractor can alsofree up one hand for the surgeon.

These are all features which are available to a surgeon in open surgery,but not in arthroscopic surgery unless using a retractor as describedherein. The intermediate portion of a retractor of the present inventionis preferably rigid enough to provide for such manipulation and toprovide for precise positioning of the expandable portion within thebody tissues. Alternatively, the intermediate portion can be flexible orselectively rigidifiable.

A retractor in accordance with the present invention is small and lightweight, and thus can be packaged under sterile conditions and bedisposable to maintain sterility. Current retractors have beenconstructed which are about 85 mm long, about 7 mm across in anunexpanded condition, and about 26 mm across when expanded. The amountof expansion can be greater or less. The dimensions will varysignificantly, of course, with the particular surgical application. Forexample, the expanding portion can be made smaller in diameter (whenunexpanded) than the body portion of the retractor. In percutaneous(fiber optic or endoscopic) abdominal or thoracic surgery, expansion ofup to 10 cm or more is needed, to move the stomach or small intestine,the greater omentum, the spleen, or the liver. The number and placementof expanding portions will vary with the application also.

Retractors have been constructed of polymers such as nylon, but can beinjection molded of other materials also. Retractors can also beconstructed of polymers, composites, and/or metals such as aluminum. Thesurface of the material can be pebbled or roughened or ridged, or haveserrated edges, to better grip tissue and hold the retractor inposition. Of course, the surface must still remain smooth enough so thatthe retractor is easily removable without damage to the tissue itcontacts.

The various portions or the retractor can be made of differentmaterials. The bladder, as mentioned, is preferably made of anelastomeric material which is strong enough to move tissue as desired. Asuitable material for the expandable bladder 130 is Silastic® elastomer,which is available from Dow Corning in medical grades. The mechanicalexpanding portion can be made of nylon for light weight and sufficientstrength. The shaft can be made of aluminum for rigidity,

The retractor also need not be straight as shown in the drawings. Theretractor can be angled or bent, for example at a 45° or 90° angle, inthe intermediate portion. Appropriate means for transmitting force at anangle are provided in such case in order to be able to shorten thesleeve to expand the arms.

Any part or all of the retractor can be made of a biodegradablematerial. For example, the mechanical expanding portion of a retractorcan be made of a biodegradable material, and can be made detachable fromthe remainder of the retractor. Similarly, the expandable bladder can bemade of a biodegradable material, and can be made detachable from theremainder of the retractor. In such a case, the biodegradable portioncan be detached and left in the body after surgery. This is useful, forexample, to prevent adjacent tissue planes from scarring together aftersurgery. The biodegradable mass will in time disappear, allowing thetissues to adjoin after they are healed.

The expandable portion 60 or the expandable bladder 130, or even theentire retractor, can be made of a transparent material to provide abetter view of the operating area and improved visualization.

The amount of expansion of the retractors can be varied. Retractors ofthe present invention can be constructed which will expand up to 600% ormore, and from as little as a few millimeters up to about tencentimeters or more, dependent on the location of use. This range ofexpansion is unattainable by any other available device.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications. Suchimprovements, changes and modifications within the skill of the art areintended to be covered by the appended claims.

I claim:
 1. A method of creating an anatomical space in body tissue bydissecting a first layer of tissue from a second layer of tissue along anatural tissue plane, said method comprising the steps of:making anincision in the body which provides access to the natural tissue plane;inserting a substantially rigid member having a bladder disposed on adistal portion thereof through said incision, said bladder being capableof exerting sufficient force when inflated to dissect the first layer oftissue from the second layer of tissue; moving said member along thenatural tissue plane to a location where it is desired to create theanatomical space between said first and second tissue layers; inflatingsaid bladder to dissect said first layer of tissue from said secondlayer of tissue along the natural tissue plane to create the anatomicalspace; deflating said bladder; moving said member to a new locationbetween said tissue layers; and inflating said bladder again to causefarther dissection of said first and second layers of tissue and toenlarge the anatomical space.
 2. A method as set forth in claim 1wherein said substantially rigid member includes a pair of jaw membersactuated by said bladder and wherein said step of inflating said bladderto dissect said first layer of tissue from said second layer of tissueincludes pressing one of said jaw members against one of said layers oftissue under the influence of force applied against an inner surface ofsaid one jaw member by said bladder.
 3. A method as set forth in claim 1wherein said substantially rigid member includes a jaw member andwherein said step of moving said substantially rigid member along anatural tissue plane to a location where it is desired to create theanatomical space between said first and second layers of tissue includespositioning said jaw member between said layers of tissue, and said stepof inflating said bladder to dissect said first layer of tissue fromsaid second layer of tissue includes pivoting said jaw member about anaxis at a distal end portion of said substantially rigid member underthe influence of force transmitted from said bladder to said jaw memberas said bladder expands and pressing an outer side surface of said jawmember against one of said layers of tissue as said jaw member pivotsabout said axis at said distal end portion of said substantially rigidmember.
 4. A method as set forth in claim 1 wherein said substantiallyrigid member includes an axially tapered distal end portion and whereinsaid step of moving said substantially rigid member to a location whereit is desired to create the anatomical space between said first andsecond tissue layers includes positioning said axially tapered distalend portion between said layers of tissue, said step of inflating saidbladder to dissect said first layer of tissue from said second layer oftissue includes expanding said axially tapered distal end portion underthe influence of force transmitted from said bladder to said end portionas said bladder expands and pressing an outer side surface area of saidend portion against one of said layers of tissue.
 5. A method as setforth in claim 4 wherein said step of deflating said bladder includescontracting said axially tapered distal end portion, said step of movingsaid substantially rigid member to a new location between said tissuelayers includes moving said axially tapered distal end portion furtherinto said layers of tissue with said axially tapered distal end portioncontracted, and said step of inflating said bladder again to causefurther dissection of said first and second layers of tissue includesagain expanding said axially tapered distal end portion by moving saiddistal end portion under the influence of force transmitted from saidbladder to said distal end portion as said bladder is again inflated. 6.The method of claim 1 wherein said substantially rigid member includesmeans for mechanically separating tissue, and wherein said steps ofinflating and inflating said bladder again include utilizing saidbladder to actuate said mechanical separating means.
 7. The method ofclaim 1 further comprising the step of inserting a scope through theincision and viewing the creation of the anatomical space.
 8. The methodof claim 1 further comprising the step of performing a surgicalprocedure in the created anatomical space.